This may be a silly question, but I ask it still. If I have declared a shebang

#!/bin/bash 

in the beginning of my_shell_script.sh, so do I always have to invoke this script using bash

[my@comp]$bash my_shell_script.sh 

or can I use e.g.

[my@comp]$sh my_shell_script.sh 

and my script determines the running shell using the shebang? Is it the same happening with ksh shell? I'm using AIX.